在 Swing GUI 中提供空白

在使用 BoxLayout时，Box.createVerticalGlue()方法可以帮助您创建一些空白。

另一种方法是 BorderFactory.createEmptyBorder(int top, int left, int bottom, int right)，它可以帮助你在组件周围留出一些空白。

感谢 Andrew Thompson 的提醒。我最近修改了 BoxLayout，我发现 Box.createVerticalGlue()可以根据面板的大小增加一些空白，而且你不能设置空白长度的明确像素值。但是 Box.createVerticalStrut()可以做到这一点。这里是一个 MCTaRE，并显示了这两种方法的效果。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;


public class WhiteSpace extends JFrame{
static WhiteSpace whiteSpace;
DemoPanel demoPanel;
boolean withGlue;
JSpinner spinner;


public WhiteSpace(){
initialWindow();
demoPanel = new DemoPanel();
ActionPanel actionPanel = new ActionPanel();


setLayout(new BorderLayout());


getContentPane().add(actionPanel,BorderLayout.NORTH);
getContentPane().add(demoPanel,BorderLayout.CENTER);
setVisible(true);
}


public void initialWindow(){
setSize(220, 300);
setTitle("White Space");
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
//Show the window in the middle of the screen
}


/**
* @param args
*/
public static void main(String[] args) {
Runnable runnable = new Runnable() {
@Override
public void run() {
whiteSpace = new WhiteSpace();
}
};
SwingUtilities.invokeLater(runnable);
}


class DemoPanel extends JPanel{
//Show the vertical white space between label1 and label2
JLabel label1;
JLabel label2;
public void initialDemoPanel(){
setBorder(BorderFactory.createTitledBorder(getBorder(), "DemoPanel", TitledBorder.LEADING, TitledBorder.TOP, new Font("Default",Font.PLAIN,10), Color.gray));
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));


label1 = new JLabel("This is first line");
label2 = new JLabel("This is second line");
}


public DemoPanel(){
initialDemoPanel();
add(label1);
if(withGlue){
add(Box.createVerticalGlue());
}
add(label2);
}


public DemoPanel(int strutValue){
initialDemoPanel();
add(label1);
add(Box.createVerticalStrut(strutValue));
add(label2);
}
}


class ActionPanel extends JPanel{
public ActionPanel(){
setBorder(BorderFactory.createTitledBorder(getBorder(), "ActionPanel", TitledBorder.LEADING, TitledBorder.TOP, new Font("Default",Font.PLAIN,10), Color.gray));


setLayout(new BoxLayout(this,BoxLayout.X_AXIS));
JRadioButton glueButton = new JRadioButton("With Glue");
glueButton.addActionListener(new glueButtonListener());
add(glueButton);


add(Box.createHorizontalStrut(10));
//To create horizontal white space
JLabel strutLabel = new JLabel("Strut Value");
add(strutLabel);
spinner = new JSpinner(new SpinnerNumberModel(0,0,50,1));
spinner.addChangeListener(new spinnerListener());
add(spinner);
//public SpinnerNumberModel(Number value,Comparable minimum,Comparable maximum,Number stepSize)
}
}


class glueButtonListener implements ActionListener{
@Override
public void actionPerformed(ActionEvent e) {
spinner.setValue(new Integer(0));
withGlue = (withGlue == true ? false:true);
whiteSpace.getContentPane().remove(demoPanel);
demoPanel = new DemoPanel();
whiteSpace.getContentPane().add(demoPanel,BorderLayout.CENTER);
whiteSpace.getContentPane().validate();
}
}


class spinnerListener implements ChangeListener{


@Override
public void stateChanged(ChangeEvent e) {
int strutValue = (Integer) spinner.getValue();
whiteSpace.getContentPane().remove(demoPanel);
demoPanel = new DemoPanel(strutValue);
whiteSpace.getContentPane().add(demoPanel,BorderLayout.CENTER);
whiteSpace.getContentPane().validate();
}
}
}

Box.createHorizontalGlue()和 Box.createHorizontalStrut(int height)也可以使用，而且 Box.createRigidArea(Dimension d)也有制造空白的能力。

好东西

作者 Karsten Lentzsch 收集了关于 UI 设计的 陈述。特别是 本 PDF谈到了审美空白的需要。增加有意义的空间，同时也要注意杂乱无章，这样才能区分小麦和谷壳。

MigLayout有多种创造空间的方法。(在这种布局中，空间称为间隙。) 间隙可以创建在最高级别的布局约束，这是可能的 在行和列之间创建间隔，还可以在单个 组件的约束。边框周围也有特定的缺口 一个称为 insets 的容器，它有自己的特定关键字需要设置。

下面的例子创建了所有这些类型的差距:

package com.zetcode;


import java.awt.EventQueue;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import net.miginfocom.swing.MigLayout;




public class MigLayoutGaps2 extends JFrame {


public MigLayoutGaps2() {


initUI();


setTitle("Gaps");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
}


private void initUI() {


JPanel base = new JPanel(new MigLayout("flowy, ins 30, gap 15"));
setContentPane(base);


JPanel pnl1 = new JPanel();
pnl1.setBorder(
BorderFactory.createTitledBorder("Grid gaps")
);


pnl1.setLayout(new MigLayout("gap 5 5, ins 10, wrap 3"));


pnl1.add(new JButton("1"));
pnl1.add(new JButton("2"));
pnl1.add(new JButton("3"));
pnl1.add(new JButton("4"));
pnl1.add(new JButton("5"));
pnl1.add(new JButton("6"));


JPanel pnl2 = new JPanel();
pnl2.setBorder(
BorderFactory.createTitledBorder("Column gaps")
);


pnl2.setLayout(new MigLayout("wrap 3", "[]10[]"));


JLabel lbl1 = new JLabel();
lbl1.setBorder(
BorderFactory.createEtchedBorder()
);


JLabel lbl2 = new JLabel();
lbl2.setBorder(
BorderFactory.createEtchedBorder()
);


JLabel lbl3 = new JLabel();
lbl3.setBorder(
BorderFactory.createEtchedBorder()
);


pnl2.add(lbl1, "w 40, h 110");
pnl2.add(lbl2, "w 40, h 110");
pnl2.add(lbl3, "w 40, h 110");


JPanel pnl3 = new JPanel();
pnl3.setBorder(
BorderFactory.createTitledBorder("Row gaps")
);


pnl3.setLayout(new MigLayout("wrap", "", "[]15[]"));


JLabel lbl4 = new JLabel();
lbl4.setBorder(
BorderFactory.createEtchedBorder()
);


JLabel lbl5 = new JLabel();
lbl5.setBorder(
BorderFactory.createEtchedBorder()
);


JLabel lbl6 = new JLabel();
lbl6.setBorder(
BorderFactory.createEtchedBorder()
);


pnl3.add(lbl4, "w 150, h 20");
pnl3.add(lbl5, "w 150, h 20");
pnl3.add(lbl6, "w 150, h 20");


JPanel pnl4 = new JPanel();
pnl4.setBorder(
BorderFactory.createTitledBorder("Component gaps")
);


pnl4.setLayout(new MigLayout());


pnl4.add(new JLabel("Name:"), "gapright 5");
pnl4.add(new JTextField(10), "gapbottom 20, gaptop 20");


base.add(pnl1);
base.add(pnl2);
base.add(pnl3);
base.add(pnl4);


pack();
}


public static void main(String[] args) {


EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
MigLayoutGaps2 ex = new MigLayoutGaps2();
ex.setVisible(true);
}
});
}
}

我们在布局中有四个面板。每个面板都有一个 MigLayout管理器。

JPanel base = new JPanel(new MigLayout("flowy, ins 30, gap 15"));

此行创建容器插入和面板之间的垂直间隔。

pnl1.setLayout(new MigLayout("gap 5 5, ins 10, wrap 3"));

在这里，我们为整个网格结构应用间隙，并设置容器间隙。

pnl2.setLayout(new MigLayout("wrap 3", "[]10[]"));

此行在列之间创建间隔。

pnl3.setLayout(new MigLayout("wrap", "", "[]15[]"));

行间隔使用此代码定义。

pnl4.add(new JLabel("Name:"), "gapright 5");
pnl4.add(new JTextField(10), "gapbottom 20, gaptop 20");

最后，可以在各个组件之间创建间隔。

每当我遇到这个问题，我就使用 JPanels:

JFrame frame = new JFrame;
frame.setLayout(new GridLayout(2, 0));


//We want the bottom left to be blank
frame.add(new JLabel("Top Left"));
frame.add(new JLabel("Top Right"));


//This is the position we want empty
frame.add(new JPanel());


//Now we can continue with the rest of the script